In this study, cellulose nanofiber (CNF) production was attempted by using a batch-type kneader with six twin-screw elements. Screw elements were twisted with 22.5 degrees to generate a high shearing force. The obtained fibrillated products showed a nanoscale morphology, indicating the effectiveness of using a batch-type kneader. For better CNF dispersion in the polymer matrix, CNFs were first distributed in polycaprolactone (PCL) with a low melting temperature to avoid the vaporization of water in a CNF-water solution and then this composite was further mixed with polypropylene (PP) at 180 degrees C. The distributions of the PCL domain and CNF in PP were improved by the addition of maleic anhydride-grafted-PP. The elastic modulus of the hybrid composite thus obtained was increased by the addition of only 1% CNF. The crystallization of both polymers in the composites started at a higher temperature than in neat polymers during cooling DSC scanning. (C) 2010 Elsevier Ltd. All rights reserved.